Temperature indicator



March 1, 1932. T' MOULDW 1,847,438

TEMPERATURE I NDI CATOR Filed June 25, 1928 Zlwvemtoz THOMAS G. MQULDING 35% /2 %MW, a; Gummy Patented Mar. 1, 1932 UNITED STATES PATENT OFFICE THOMAS G. MOULDING, OF FLINT, MICHIGAN, ASSIGNOR TO A C SI PAR'K PLUG COMPANY,

OF FLINT, MICHIGAN, A COMPANY'OF MICHIGAN TEMPERATURE INDICATOR Application filed .Tune 2s,

This invention relates to an improved bulb for temperature lndlcatlng instruments, and

has particular reference to the type of instruments used on internal combustion engines of automotive vehicles.

In the conventional form these instruments consist of a suitable pressure gage connected by means of tubing to a bulb adapted to contain a temperature responsive fluid. The

bulb is exposed to the heat of the body the temperature of which is to be measured and the resultant expansion of the fluid in the be caused by excessivevibration, such as in the case of high speed internal combustion engines, or by the tube when in use.

I accomplish the object of the invention by a novel method of attaching the tubing to the bulb, and in practice I prefer to use tight fitting and subsequently soldered joints at the ends. In the preferred form the tubing 3 extends completely through the bulb with a projecting closed tip at the free end. A portion of the tube wall is cut away within the bulb so that the fluid may exert a pressure in the tubing and so that the fluid may be injected into. the bulb in manufacture. It is clear that with the tube extending completely through the bulb a more rigid connection can be made and one that will not become loose due to vibration.

Tighter soldered joints are made possible in the preferred form, by the novel shape of r the bulb at the free end, and by the novel relation between the bulb and the bushing at the jam nut end.

At the free end the bulb is bent so as to re-enter the open end, and when the tube is inserted the curved end thus formed provides a pocket for solder. At the jam nut end the bulb, bushing and tube form another pocket 59 for solder.

pressure built up in the 1928. Serial No. 287,737.

A modified form of jam nut end consists in having the bulb projecting entirely through the bushing and being spun over at the end, thus providing a pocket for solder and making it necessary to unite only two surfaces instead of four.

In a modified form the tubing does not extend completely through the bulb but terminates about midway. An orificed plug is pressed into the bulb and against a bead near the open end and is soldered in place. After the tube has been filled the orifice is plugged up with'a suitable pin.

In the drawings; p

Figure 1 shows a section through the improved bulb, with the tube and all joints sealed, and with strengthening wire wound about the tube. A

Figure 2 is a side view of the assembled,

bulb and tubing with the jam nut applied.

Figure 8 shows a typical bulb installation and the method of attaching the tube to a suitable pressure gage.

Figure 4 shows a modified form of bulb and means for attaching to a bushing.

Figure 5 is a view of another modification. Referring to the drawings, the numeral 10 indicates the bulb which is generally of cylindrical form and has open ends, and is filled with a suitable heat responsive liquid. The free end 12 of the bulb has its edges rebent or inturned as shown at 14, and spaced from the walls of the bulb 10 as shown at 16. The opposite end of the bulb is swaged or reduced in diameter as shown at 18 and surrounding this reduced or swaged portion. is a bushing 20, the inner surface of which substantially conforms to the surface of the swaged portion. This swaged portion has a tapered part shown at 22. If desired, the tube end may be left, straight and a bushing or collar inserted between the bulb and tube.

The swagedend 18 does not extend entirely through the bushing, but slightly short thereof, as shown at 24.. This will leave a small f pocket 25 at the end of the bulb bushing formingtheiwalls.

Extending entirely through the bulb 10 is a slender tube 26 having the bore 28 and a cut out portion 30 within the bulb 10 to alwith the low the expansive fluid to have access to the bore 28. This structure allows for a ready filling of the bulb. The free end 32 of the tube 26 extends outwardly of the bulb 10 and after filling the latter the end is preferably closed as shown at 34 by pinching or pressing the walls of vthe tube together and thereby forming a liquid tight connection. If desired, a plug or other suitable closure for-the tube end maybe, used. From the structure as described it will be seen that the pressure tending to force the tube out of the bulb is equal in both directions. The two forces are therefore resisted by the tensile strength of the tube as well'as by thestrength of the soldered joints The tube 26 forms a relatively close fit with the rebent portion 14 of the bulb 10 and in order to make ,a liquid tight seal, solder shown at 36 is poured. into the pocket 38 --formed between the rebcnt portion and the tube 26. This solder will form a liquid tight joint due to it'smolecula-r adherence to the metal surfaces of the tube 26 and the bulb 10.

If desired, the end 12 may be left straight and reduced by swaging, as is shown at 18 at the opposite end of the tube, thereby eliminating the rebent portion. This swaged end may have, a somewhat flared or conical mouth portion to form a pocket acent the tip end of the tube and by filling this pocket with solder a liquid tightoint is obtained. The tip 32 will project from the bulb end as shown in Figure 1.

The opposite orswaged end of the bulb is also filled'with solder in order to forma liquid tight connection. This solder fills the pocket 25 formed between the space: above the swaged'end of thebulb 10 and the outer lane of the bushing 20." In case there should .e' anyv space between the bulb l0 and the bushing 20, the solder will flow thereintov as shown at 40 in Figure l. The swaged end 18 forms a very close contactwith the tube 26,

however, should there be any slight space between the two, the solder will also flow thereinto and due to the molecular adherence will form a very intimate and liquid tight connection.

The bulb may be applied to any suitable container as shown in Figure 3. For pur poses ofillustratiomfl have used the cooling system, of aninternal; combustion engine, the piping of which isshown at 42/ -Tothis piping there is applied the boss 44:, and. in the opening of this boss there is received the threaded portion 46 of'a jam nut 4:8. The jam nut has a bore forthe reception of the tubing 26 and the inner or threaded end thereof-abi'itjs against a shoulder 50 on the bushing 20. The bushing 20 has a further shoulder 52 which rests on a} corresponding shoulder 54' in the boss 4-4,? and when the jam nut 4E8'is screwed home, it wi1l,l 1oldthe tive vehicle, and is therefore adapted for.

reading at a distance on the bulb.

As a modification of the structure of Fig ure 1, I usetl-ie construction shown in Figure 4. In this species the tube 10 has its free end open and is closed by means of a plug 62 having a central opening 64-. The plug rests against a bead 66 pressed in the bulb side and is secured in position preferably by soldering, while a suitably tapered pin 68 closes the opening 6% in the plug 62. The purpose of the opening to allow the insertion of a suitable expansive fluid.

The tube 26 of t iis species does not ex tend entirely through the bulb 10, but is considerably short of its inner end as shown at 70 in Figure The opposite end of the bulb 10- has a swaged portion 18 similar to that shown in Figure 1, except that it extends entirely through the bushing 20, and has its end spun or turned over as shown at T2 to overlap the outer surface of the bushing 20 and thereby hold it in place. This spun over portion will form a small pocket 7% adjacent the tube 26 whichinay be filled with solder in order to form a liquid tight, connection. This arrangement leaves but the surfaces between the swagec. end and the tube 10 to be closed eliminating the surfaces between the swaged end 18 and the bushing 20.

The spaces 76 within the bulbs 10 or 10 is filled with a suitable liquid which is readily responsive to changes in heat and whose expansion will be registered through the intermediary of the tube 26 on the gage 58.

By referr ng to thestructure of Figure 1 it will be seen that due to the fact that the tube 26 extends entirely through the bulb 10, a more rigid and intimate connection with the bulb is attained, and as no free end is exposed there will be no tendency for the liquid to press thereagainst and in this way interfere] with the accurate working of the bulb. "rioreover, due to the space 16 between the inturned end 14 and wall of the bulb 10, the pressure exerted by the liquid within the bulb will tend to press the bent ever end l l The end has a soldered liquid tight joint 36 between the tube 26 and the bulb 10.

I claim:

1. In a heat responsive instrument, a bulb adapted to contain a heat sensitive fluid and having one end portion turned on itself, and a tube passing through said end and bulb and having an opening communicating with the interior of said bulb.

2. In a heat responsive instrument, a bulb having one end inturned and spaced from the walls of the bulb, said end having a opening,

of the class described, an elongated bulb havin openings at its ends, a slender tube ex tending through said bulb at its openings and having one end seated, means fastening the ends of said bulb to said tube, a portion of said tube within said bulb being cut away.

5. In a temperature responsive instrument of the class described, a bulb having a free end and a jam nut end, a slender tube fastened in said bulb and having an opening communicating with the interior ofthe bulb, a bushing surrounding the jam nut end of said bulb, there being a pocket at said jam nut end, a material in said pocket to join said tube and bulb molecularly, and means to seal the free end of said bulb.

6. In a temperature responsive instrument of the class described, a bulb having a free end and a am nut end, a slender tube extending completely through said bulb and having one end sealed, means to fasten said bulb to said tube at the jam nut end, a reentrant surface on said free end, a pocket formed by said surface and said tube, a material in said pocket to join said tube and bulb molecularly, and a cut away portion on said tube within said bulb.

7. In a heat responsive instrument having a bulb, a bushing, a reduced end on said bulb extending into said bushing, said end extending short of the outer plane of the bushing, and a solder seal between said bushing and end.

8. In a device of the class described, a bulb adapted to contain a heat sensitive fluid and v having its ends reduced and left straight, a

tube in said bulb having an opening coinmunicating with the interior thereof and passing through said reduced ends, and a liquid tight joint between said tube and bulb.

9; In a heat responsive instrument, a bulb adapted to contain a heat sensitive fluid and having a reentrant end, a bushing at the other end, and a tube passing through both said ends and said bulb and having an opening communicating with the interior of said bulb, said tube being closed at one end.

10. In a heat responsive instrument, a bulb adapted to receive a heat sensitive fluid and having one end portion turned on itself, atube passing through said end and entirely through said bulb, said tube having an opening communicating with the interior of said bulb, and a liquid tight joint between said turned over portion and said tube.

11. In a heat responsive instrument, a bulb adapted to receive a heat sensitive fluid and having one end portion turned on itself and spaced from the walls thereof, and a tube passing through said end and entirely through said bulb, said tube having an opening co1nmunicating with the interior of said bulb.

12. In a heat responsive instrument, a bulb adapted to receive a heat sensitive fluid and having one end portion turned on itself, a tube passing through said end and bulb and having an opening communicatingwith the interior of said bulb, said turned end forming a recess adjacent the tube, and a soldered joint formed at said recess.

In testimony whereof I afliX my signature.

THOMAS G. MOULDING. 

